__error generated types should use ErrorLoad instead of Load.

[f-elix]

Describe the bug

The types generated at ./.sveltekit/types/src/routes/__error.d.ts by Sveltekit use the generic Load function type instead of the ErrorLoad type, which causes errors to show up when using the error and status parameters in the function.

Reproduction

https://github.com/f-elix/sveltekit-generated-types-error

You can open this repo in vscode to see the errors in __error.svelte. npm run check will also display the errors in the terminal.

Logs

No response

System Info

System:
    OS: Windows 10 10.0.22000
    CPU: (8) x64 Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz
    Memory: 26.30 GB / 39.76 GB
  Binaries:
    Node: 16.14.2 - C:\Program Files\nodejs\node.EXE
    npm: 8.5.0 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Spartan (44.22000.120.0), Chromium (98.0.1108.43)
    Internet Explorer: 11.0.22000.120
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.33
    @sveltejs/kit: next => 1.0.0-next.301
    svelte: ^3.44.0 => 3.46.4

Severity

annoyance

Additional Information

I can use the ErrorLoad type provided by Sveltekit to work around that.

[Rich-Harris]

Relatedly, I sort of wonder if we shouldn't just have a single Load type where status and error are both null in the default case. (This thinking also prompted by the addition of page endpoints, which mean that a non-error load can be called even if the status code is a 4xx/5xx, even though we're not currently using it — #4328)

[Rich-Harris]

Going to close this in favour of #4461, where we're plotting the removal of ErrorLoad altogether